The ability to generate functional beta cells from pluripotent and adult stem cells will provide access to unlimited numbers of these cells for transplantation for the treatment of type 1 diabetes, for studying their role in disease states and for screens aimed at defining the mechanisms by which key regulators control their proliferation and maturation. This proposal outlines an integrative series of studies by seven different research groups that combine tissue engineering and cell-processing strategies with stem cell and endothelial cell biology to generate functional islet like structures with differentiated cells generated from human embryonic stem cells, human induced pluripotent stem cells (collectively referred to as pluripotent stem cells) and adult pancreatic stem cells. The first aim focuses on defining the signaling pathways and cellular interactions that regulate development and maturation of insulin producing cells from pluripotent stem cells. The second aim will use similar approaches to study the regulatory pathways and cell populations that control the proliferation and differentiation of a recently identified stem cell in the adult human pancreas. The experiments outlined in the third aim focus on generating endothelial progenitor populations from different sources and investigating the capacity of these populations to promote beta cell differentiation, survival and maturation. The goal of the final aim is to test the function of the cell populations and engineered tissues generated in the project by transplantation into different mouse models of diabetes. The outcome of these studies will provide important new insights into the regulation of beta cell development and maturation from stem and progenitor populations in culture. This information will be instrumental in developing strategies for the routine and large-scale production of functional beta cells in culture and for promoting regeneration from stem cells within the pancreas. These advances will pave the way to develop novel beta cell replacement and/or beta cell regeneration therapies for the treatment of type 1 diabetes.